Existing technologies for navigation are not without shortcomings. For example, global positioning system (GPS) based navigation systems require good signal reception from satellites in orbit. With a GPS-based system, navigation in urban areas and indoor navigation is sometimes compromised because of poor signal reception. In addition, GPS-based systems are unable to provide close-quarter navigation for vehicular accident avoidance. Other navigation systems suffer from sensor errors (arising from slippage, for example) and an inability to detect humans or other obstacles.